London  - A unique motorbike with a mounted machine gun is up for sale nearly a century after it was built for the First World War.

The dangerous vehicle was intended to be used by the Russian army, and kitted out with cutting-edge weaponry attached to the sidecar. However, by the time it was ready for delivery Lenin had pulled out of the war in the wake of the Russian Revolution, and it was never deployed in battle.

A lot of 250 Matchless motorbikes had to be auctioned off in 1918, fetching £64 each - but now one of the few remaining models is set to be sold for £30,000. Registration papers show the bike’s first owner was Edward Foster, from Dorchester in Dorset, but little is known of its history until it was bought by First World War enthusiast Chris Roberts in 1998.

The bike was in near-perfect condition, because it was apparently stored indoors in dry conditions for at least 60 years. Mr Roberts, a member of the Great War Society, set about restoring the bike to its wartime specification - which included adding the Vickers machine gun which would originally have been attached.

The gun, which is deactivated, can be fitted to three separate mounts on the bike allowing the gunner to fire in all directions. The motorbike is one of only three wartime machine-gun bikes in the country - the other two are in museums - and is the only surviving one made by Matchless.

It is expected to fetch between £25,000 and £30,000 when it goes under the hammer at London auctioneers Bonhams on Saturday.

James Stensel, from Bonhams’ motoring department, said: ‘This bike has a particularly interesting history - a batch of 250 of these bikes was manufactured in Britain in 1917 for the Russian military, our allies, but they then dropped out of the war and the bikes were no longer needed. ‘Instead they were auctioned off and bought by private collectors for civilian use.

‘This example didn’t see military action. It would have been at a British port ready for dispatch to the Russian Army but when they cancelled the order it was sold off. ‘When the machines were readied for dispatch they would have consisted just of the motorcycle and the sidecar. The Russians would have then added their own military hardware.

‘The Vickers machine gun on this bike is a later edition but is just like the ones that would have been mounted on these bikes in the war.

‘It’s got an anti-aircraft machine-gun mount allowing the gunner to shoot in any direction. The machine gun is also detachable and fully telescopic so if you wanted you could take it off the bike and use it separately.

‘The outfit can seat three people - one on the main saddle, another on a pillion saddle and a third in the sidecar. These would have been the ultimate motorbike attack vehicles of their day. ‘They’re incredibly rare now - you only ever see them in museums and never in auctions. There are only three known to exist in the UK and this is the only one made by Matchless. ‘Not only is it a part of Russian military history but of ours as well. In 1917 Britain was producing the most advanced motorcycles in the world and this no exception.’